GEOPH424 Final: GEOPHYS 424 UofA Final Exams 2013 424 Final
Document Summary
Tuesday april 23rd 2013, 9 am noon. Cell phones and all other electronic devices must be switched off and stored. All questions must be directed to the invigilator. Question 1 : maxwell"s equations (total points = 18) A low frequency electromagnetic (em) wave is vertically incident on the earth"s surface. The em fields vary with time as e with angular frequency i t. At this location, the earth has a uniform conductivity = 0. 001 s/m. The electric field is polarized in the x-direction and ex does not vary in the x-direction. Displacement current can be ignored (1a) use maxwell"s equations to show that in the earth the electric field ( ex ) satisfies the following partial differential equation. E iw x (7 points) (1b) consider a non-plane wave whose amplitude varies with y as : zye x ze x sin( Show that in this case, the partial differential equation in (a) simplifies to an ordinary differential equation.
